Height perception and paranoia

Experiment in virtual reality shows that reducing a person's height can increase feelings of vulnerability and raise levels of paranoia

Experiencing the world from lower down than usual can increase how mistrustful and paranoid people feel, according to research in a virtual world.

Scientists believe that feelings of persecution were triggered when people lost height and suffered a fall in self-esteem, which led them to see themselves as inferior and more vulnerable.

The findings could help researchers develop more effective psychological treatments for severe paranoia, through simulations that let patients confront and overcome their delusions.

Scientists at Oxford University recruited 60 adult women who had reported feelings of paranoia in the month beforehand. Each donned a virtual reality helmet and took two virtual tube rides, complete with computer-generated passengers that nattered around them.

While most of the women sensed there was something strange about one of the rides, few realised this was down to the scientists lowering their height, and so their point of view, by around 30cm.

To see how the change in perspective affected the virtual passengers, the researchers asked the women to fill out two questionnaires before and after the rides. One measured how well the women felt they compared to others, such as being more or less talented, or more or less attractive. The second questionnaire provided a paranoia score by asking them to rate statements like "someone had it in for me" on a scale from one to five.

The results, published in the journal Psychiatry Research, show that the women's social comparison scores fell on average from 60 to 52 when they saw the world from lower down. At the same time, their paranoia scores rose from 12 to 14.

"When you are lower down than normal, it makes you feel more inferior to other people, and that I think makes you feel more vulnerable, and that's what leads you to see hostility where there isn't any," said Daniel Freeman, a professor of clinical psychology who led the study.

"It's not saying that short people have greater levels of paranoia, it's about what happens when your own normal height is reduced in social situations," he added.

Freeman said the work could help researchers to find better ways to treat paranoia by boosting people's self-esteem. One way might be to artificially raise their height in a virtual world to give them more confidence than normal, and gradually reduce it. One unknown is how long the effects last for.

Willem-Paul Brinkman, who works on virtual reality therapy for people with mental health problems at Delft University in the Netherlands, said the work added to other studies that show that giving people taller avatars in a virtual world made them more confident negotiators, while giving them a more attractive avatar made them more intimate towards others.

Brinkman said the latest study showed the potential for VR to treat patients whose paranoid thoughts interfered with their daily life. "Giving therapists the ability to put patients in a VR environment and discuss these thoughts when they are actually experiencing them, could be very beneficial. At the moment, therapists have to rely on the patient's recollections of these experiences."

The challenge, he said, was to find triggers to provoke feelings of paranoia. The ethnicity of an avatar might be one trigger, but changes to a person's height could be another. "These triggers might affect individuals differently, so it would be good to offer therapists a number of them so they can tailor it to the needs of the patient," Brinkman said.